Mulberry leaf extracts give glimpse of hydrocolloids future

An extract from the leaves of the mulberry bush may act as a
hydrocolloid, with potentially unique properties for food
formulators, says new research from Taiwan.

A water extract of the mulberry leaf provided a hydrocolloid
composed of mainly carbohydrate with high levels of uronic acid,
indicating the ionic nature of the hydrocolloid, report the
researchers in the journal Food Hydrocolloids​.
"We found that mulberry leaf hydrocolloid possess unique
rheology, particularly for the stiffer backbone as compared to
other polysaccharide gums,"​ wrote Hsiang-Yun Lin and Lih-Shiuh
Lai from National Chung Hsing University.
"Furthermore, since the rheological properties of mulberry leaf
hydrocolloid was strongly affected by the ionic strength and ion
types, it is expected that rheological behavior of functional foods
containing mulberry leaf hydrocolloids can be modulated by
adjusting the ionic strength and ion types in food systems, and
deserve further investigation to merit new application in the
future." ​
The findings may be welcomed since the cost of nearly all
hydrocolloids have increased in the last year due to rocketing
energy, raw material and transportation costs, according to
hydrocolloid information service IMR's Quarterly Review.
Emulsion stabilizers, suspending agents, gelling agents,
thickeners, fiber sources, mouthfeel improvers, fat replacers and
processing aids all come under the umbrella of hydrocolloids. This
market has grown significantly in the past 20 years in parallel to
an increasingly complex food processing industry.
The food industry's most frequently used hydrocolloids include:
agar, alginates, arabic, carrageenan, Carboxy Methyl Cellulose
(CMC), gelatin, konjac flour, locust bean gum (LBG), Methyl
Cellulose and hydroxypropyl Methyl Cellulose (MC/HPMC),
microcrystalline cellulose (MCC), pectin, starch and Xanthan.
A potential new member of this team, if further research backs up
the promising early studies, could be hydrocolloid from mulberry
leaves.
Characterization of mulberry
hydrocolloid ​
Using deionized water, Lin and Lai prepared extracts of mulberry
leaves. The average molecular weight of the carbohydrate part of
thaws found to be 600,000, which was reportedly similar to values
for low methoxy-pectin (540,000).
The relative chain stiffness parameters for the hydrocolloid were
in the range of 0.004-0.013, which is indicative of a stiff
backbone.
According to the researchers, studies on the rheological aspects of
mulberry leaf hydrocolloid or relatively limited and this is one of
the most extensive.
"During the development of functional foods containing mulberry
leaf hydrocolloid or mulberry leaf extracts, viscometric properties
should play an important role,"​ they stated.
Source: Food Hydrocolloids​
Published online ahead of print, doi:
10.1016/j.foodhyd.2008.03.018
"Isolation and viscometric characterization of hydrocoloids
from mulberry (​Morus alba L.) leaves" ​Authors:
H.-Y. Lin, L.-S. Lai